Climategate: What Did Phil Jones Actually Admit? Was He Correct?

Phil Jones is director of the Climatic Research Unit (CRU) at the University of East Anglia (UEA), which has been at the center of the row over hacked emails. The BBC’s environment analyst Roger Harrabin put questions to Professor Jones yesterday, including several gathered from climate skeptics.

Here are some of the questions. Some of Phil’s replies were surprisingly candid. I will look at and comment on six of the 23 questions.

Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

Phil Jones admitted the warming trends in the cyclical climate change we have seen since 1860 have been similar in magnitude. He provided these values for those periods:

Period Length Trend Significance

1860-1880 21 years 0.163 Yes

1910-1940 31 years 0.150 Yes

1975-1998 24 years 0.166 Yes

Jones left out 1880 to 1910, and 1940 to 1976, which both had negative decadal trends.

Do you agree that from January 2002 to the present there has been statistically significant global cooling?

Here Jones noted that the trend from 2002 to 2009 is negative (-0.12C per decade), but not statistically significant. He had noted earlier in the interview:

Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.

Do you agree that natural influences could have contributed significantly to the global warming observed from 1975-1998?

When considering changes over this period we need to consider all possible factors (so human and natural influences as well as natural internal variability of the climate system). Natural influences (from volcanoes and the Sun) over this period could have contributed to the change over this period.

However, Jones also noted that volcanoes should have produced cooling (and did) in the early 1980s and 1990s. He said the solar was flat. Here, it actually depends on what and whose measure of solar output you use.

Some, like Judith Lean, show flat solar output, but others like Hoyt/Schatten/Willson show an increase in line with recent decadal warming. Also, the other solar factors like ultraviolet (Shindell and Labitzke) and geomagnetic (Svensmark, Friis-Christensen), which can influence Earth’s temperature through ozone chemistry or cosmic ray cloud cover variations, were ignored by Lean and the IPCC (though they were discussed at some length in the IPCC science chapters). Scafetta and West have shown that, depending on which reconstruction is used and assuming that they are proxies for the total solar effect, you can explain up to 69% of the government (inflated) warming since 1900.

Skeptics of anthropogenic global warming (AGW) suggest that the official surface record paints a different story from the actual station records. To restore trust, should we start again with new quality control on input data in total transparency?

There is more than one “official” surface temperature record, based on actual land station records. There is the one we have developed in CRU, but there are also the series developed at NCDC and GISS. Although we all use very similar station datasets, we each employ different ways of assessing the quality of the individual series and different ways of developing gridded products. The agreement between the three series is very good.

That is because NCDC and CRU do not adjust for urbanization -- even though Tom Karl, director at NCDC, suggested in a 1988 peer review paper an urban contamination of 3.73°C for a city of 5 million. Phil Jones himself, in a 2009 paper on China, found a countrywide urban contamination of 1C per century. GISS does adjust for urbanization, which results in much less U.S. warming. For the globe, their metadata base of station location/population is poor. And Steve McIntyre found they just as often adjust urban temperature trends up as down.

There is a debate over whether the Medieval Warm Period (MWP) was global or not. If it were to be conclusively shown that it was a global phenomenon, would you accept that this would undermine the premise that mean surface atmospheric temperatures during the latter part of the 20th Century were unprecedented?

There is much debate over whether the Medieval Warm Period was global in extent or not. ... Of course, if the MWP was shown to be global in extent and as warm or warmer than today ... then obviously the late-20th century warmth would not be unprecedented.

The Idsos at CO2 Science have done a very thorough job documenting, using the peer review literature, the existence of a global MWP. They have found data published by 804individual scientists from 476 separate research institutions in 43 different countries supporting the global Medieval Warm Period.

Where do you draw the line on the handling of data? What is at odds with acceptable scientific practice? Do you accept that you crossed the line?

No answer. Matter for the independent review.

Anthony Watts, E.M. Smith, and I have shown in "Surface Temperature Records: Policy Driven Deception" that the surface temperature records leave a lot to be desired. Claims about global monthly and annual rankings, and that the last decade was the warmest ever, can be dismissed as folly.